Immunotoxicity of Silver Nanoparticles (AgNPs) on the Leukocytes of Common Bottlenose Dolphins (Tursiops truncatus)

Abstract

Silver nanoparticles (AgNPs) have been extensively used and are considered as an emerging contaminant in the ocean. The environmental contamination of AgNPs is expected to increase greatly over time, and cetaceans, as the top ocean predators, will suffer the negative impacts of AgNPs. In the present study, we investigate the immunotoxicity of AgNPs on the leukocytes of cetaceans using several methods, including cytomorphology, cytotoxicity, and functional activity assays. The results reveal that 20 nm Citrate-AgNPs (C-AgNP20) induce different cytomorphological alterations and intracellular distributions in cetacean polymorphonuclear cells (cPMNs) and peripheral blood mononuclear cells (cPBMCs). At high concentrations of C-AgNP20 (10 and 50 μg/ml), the time- and dose-dependent cytotoxicity in cPMNs and cPBMCs involving apoptosis is demonstrated. C-AgNP20 at sub-lethal doses (0.1 and 1 μg/ml) negatively affect the functional activities of cPMNs (phagocytosis and respiratory burst) and cPBMCs (proliferative activity). The current study presents the first evidence of the cytotoxicity and immunotoxicity of AgNPs on the leukocytes of cetaceans and improves our understanding of environmental safety concerning AgNPs. The dose-response data of AgNPs on the leukocytes of cetaceans are invaluable for evaluating the adverse health effects in cetaceans and for proposing a conservation plan for marine mammals.

Th2 cytokine bias induced by silver nanoparticles in peripheral blood mononuclear cells of common bottlenose dolphins (Tursiops truncatus)

“…Although the down-regulation of mRNA expression levels may be associated with decreased RNA synthesis due to the direct interaction between C-AgNP 20 and RNA polymerase, it cannot fully explain the unaffected Th2 cytokines (IL-4 and IL-10) of cPBMCs in this study. On the other hand, the ConA-induced proliferative activity of cPBMCs is inhibited by 0.1 and 1.0 µg/ml C-AgNP 20 ( Li et al, 2018b ), and this phenomenon may be associated with the decreased mRNA expression levels of IL-2, IL-12, IFN-γ, and TNF-α and/or a suppressive effect on DNA/RNA synthesis induced by ConA. Further investigation on the underlying mechanism of AgNPs in cetacean leukocytes is important to ascertain the negative health impact caused by AgNPs on cetaceans, and such investigation would improve the understanding of the potential hazards of AgNPs to environmental condition and human health.…”

“…Considering the extensive use of 20 nm citrate-AgNPs (C-AgNP 20 ) in recently reported studies of cetacean and human blood cells ( Huang et al, 2016a ; Li et al, 2018b ; Poirier et al, 2014 ; Poirier, Simard & Girard, 2016 ), commercial C-AgNP 20 (Pelco ® citrate Biopure™ silver; Ted Pella, Redding, CA, USA) was chosen. The C-AgNP 20 had been extensively washed (without centrifugation) so that the level of trace elements becomes less than 0.000001%.…”

High Bactericidal Self-Assembled Nano-Monolayer of Silver Sulfadiazine on Hydroxylated Material Surfaces

“…This monolayer bears a small amount of silver, not enough to exert toxic effects on eukaryotic cells, and grants a permanent binding to the material surface, thus ensuring both stability of the antimicrobial coating and biological safety. Indeed, the firm anchorage of a simple monolayer of silver containing complex via covalent bound abolishes the risk of toxic effects for immune cells that can derive from freely circulating detached silver complexes or nanoparticles [57].…”

The Hemocompatibility of Nanoparticles: A Review of Cell–Nanoparticle Interactions and Hemostasis

“…However, NPs can suppress phagocytosis by interfering with any of the three steps involved in phagocytosis, namely attachment of the target particle, extension of pseudopodia around the attached particle and engulfment of the attached particle into a phagosome. If NPs cause defeat in any one of these steps, the result will be impaired phagocytosis with a definite alteration in the immune and inflammatory responses of neutrophils [112].…”